Overview
When using a UISplitViewController and then presenting a new detail controller, or pushing another VC onto the detail controller's nav stack, the navigation item on the master controller is activated.
Example 1
Let's say the master controller has a title of "Settings" and contains a table view with multiple rows that when tapped will load a new view controller into the details pane using showDetailViewController. The detail pane is properly updated but VoiceOver jumps to the navigation item of the master pane, so we hear "Settings".
Now we can call UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, self.view) in viewDidAppear of the view controller we're displaying but we'll still hear "Settings" a moment before. Moving where we post the accessibility notification into viewDidLoad or viewWillAppear does not make a difference.
Example 2
Similarly if we push another view controller onto the nav stack of whatever controller is in the detail pane "Settings" once again gets activated.
Now the iOS Settings (on iOS 11) app handles this differently. When you select an item in the list the first cell on in the view on the detail pane is read correctly, and the "Settings" navigation item is not read. How can I mimic this behavior?
Related
I'm working with the Xcode view editor and Swift.
I have my main view which contains a tab bar controller with 2 tabs.
On the second tab, I have a #IBoutlet var myLabel: UITextLabel!. Inside viewWillAppear I put some text in this label.
On the first tab, I have a button which launch a third view through a Push segue, and on this new tab, I have a Back button which gets me back to the main view containing a tab bar controller (through a push segue too).
When I launch my app, go in my second tab, the text of the UITextLabel is changed.
I still can go to my first tab and navigate between them it works.
But the problem is when I click on my first tab's button, then on Cancel, then goes back to my second tab, my UITextLabel doesn't change. And I can't perform any action on it anymore. It's not nil though but it's like it's still connected to the first UITextLabel before the segue and not this one.
Where am I wrong ?
Several things are wrong.
With tabbed apps, Apple says that the tab bar controller should be the root level navigation method for the app. It should always be present, and the user should always be able to tap another tap to switch to another part of the app.
So the first tab should connect to a navigation controller. When the user pushes the button, you should push a new view controller onto that navigation controller. The tab bar will still be visible and enabled, and the user will still be able to switch to view controller one.
Next thing:
You say "I have a Back button which gets me back to the main view containing a tab bar controller (through a push segue too)."
That's very wrong. Back buttons should pop a view off of the current navigation stack. They should not be pushing anything. Any time you use a push segue, you are creating and pushing a brand new instance of a view controller, and leaving the other view controllers in the navigation stack.
I have a tabbed based iOS application. The fourth tab is linked to a UINavigationController. When I navigate to the home tab from the fourth tab, the UI elements of the home tab are pushed down. However, if I rotate the phone to landscape and then back to portrait, everything has moved up and is in the correct place.
In Storyboard, I set the top bar to none. I have the UINavigationBar hidden in the fourth tab/view controller before I navigate to the home tab.
Why would it be that the rotation fixes the constraints? How can I fix the UI elements such that they are not pushed down in the first place?
Here is a screen shot of my storyboard:
Your question doesn't really make sense. A 4th tab would not be embedded in a navigation controller. Instead, the 4th tab would link to a navigation controller. When you first select that tab you'd see the root view controller and it's navigation bar item. If you pushed a new view controller it would get pushed onto the navigation controller in tab 4. If you switch to one of the other tabs then the navigation controller will be swapped away and it's navigation bar will no longer be visible. Swap back to tab 4 you'll see it again, complete with it's navigation bar.
I created a sample app in order to confirm what I'm describing, as I haven't used tab bar controllers a lot, and not in quite a while I can upload the project if you really need to see it. It only contains a couple of lines of code (to implement the button on the navigation controller's view controller that creates and pushes a new view controller.)
I have a TabBarApplication with four views in the main TabBarItem. The problem comes when I go to any of these views and click in any button to go to another view and when I go back by a button linked to the main view, the TabBarItem of the app disappear!!
For example, one view of the app is a tableView in which each element of the list is linked to his external view and it has a back button that should return to the tableView. All the segues are by modal, not push because push segue crash the application and by modal it runs correctly but the problem comes when I returned by clicking the back button of the NavigationItem in the header of the view to his main view and the TabBarItem of the app is not there, is empty.
Each tab should have the view controller set to a navigation controller, with the view controller you want set as the root view controller of the navigation controller. Now you can use push segues and the standard back button that will be added for you. This will bypass the issue (and work much better for you and users).
You current issue is likely related to not really ever going back. Instead, just always presenting new modal view controllers which replace any existing content on screen.
What I have is a Master view that is embedded in a nav controller and when you push a button it navigates to a different master view and causes a replace segue for the detail view.
What I would like is when the automatic "back button" is pressed, the detail view goes back to the "title" version which I'm using as a splash screen.
Things I've tried so far
Delegating UINavigationBar
Manually forcing a segue when the Master view associated with it's "linked" detailview goes off screen
Okay, figured it out.
Need to get the "splash page" to call the segue. I did do this, BUT I did it with "replace" type, which doesn't allow for "pop" transitions
I have a storyboard setup as a Tabbed Application with first view controller containing a
UITableView. The Protoype cell has a "push" segue to detail view which is embedded in a navigation controller. So far so good. The detail view pushes when a cell is selected and there is a navigation bar item to get back to the table view.
Now I run into trouble. The detail view has 2 buttons "Map" and "Ticket". If I create a new UIViewController, embed it in a navigation controller, and ctril-drag a 'push' segue from a button to the new view controller as before, the app crashes instantly with a SIGABRT when I click the button. If I don't embed in nav controller and use a 'modal' segue instead it doesn't crash but it seems a natural flow to continue with the 'horizontal slide' animation and the nav bar button back to the detail view.
Once I can stop that crashing I would like to connect the other button to it's own view controller with a UIMapView.
What am I doing wrong?
You don't need to embed a navigation controller in the detail view. You only need one at the top level. Take out the navigation controller in the detail view controller and just do a push from there to the next view.